640180636 has 12 divisors (see below), whose sum is σ = 1121422680. Its totient is φ = 319774160.

The previous prime is 640180631. The next prime is 640180691. The reversal of 640180636 is 636081046.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (640180631) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 74455 + ... + 82606.

It is an arithmetic number, because the mean of its divisors is an integer number (93451890).

Almost surely, 2^640180636 is an apocalyptic number.

It is an amenable number.

640180636 is a deficient number, since it is larger than the sum of its proper divisors (481242044).

640180636 is a wasteful number, since it uses less digits than its factorization.

640180636 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 158084 (or 158082 counting only the distinct ones).

The product of its (nonzero) digits is 20736, while the sum is 34.

The square root of 640180636 is about 25301.7911618921. The cubic root of 640180636 is about 861.8549451496.

The spelling of 640180636 in words is "six hundred forty million, one hundred eighty thousand, six hundred thirty-six".